Brigadier General Ahmad-Reza Pourdastan said Tuesday that the Iranian army warned the ISIL about any potential movement toward the Iranian border since the very beginning of the terrorist group's incursion into Iraq.

"When ISIL Takfiri terrorists penetrated western Iraq and were close to the Iranian borders, the Ground Forces were fully ready to annihilate them," the commander told IRNA.

"We marked a red line 40 kilometers into the Iraqi soil and warned (them) they will face Iran's harsh response if they cross the line.

"The group received our message and fled the zone quickly," he said.

Pourdastan said that the Iranian army is fully familiar with tactics used by terrorists and closely monitors their movement inside Iraq.

The ISIL terrorist group took control of Iraq's second largest city of Mosul in June 2014, before sweeping through parts of the country's Sunni Arab heartland.

The Takfiri group, with members from several Western countries, has been carrying out horrific acts of violence such as public decapitations and crucifixions against all communities, including Shias, Sunnis, Kurds, and Christians.